[tracing] Add a dump provider to dump process memory totals.

base/trace_event/process_memory_dump.cc

Index: base/trace_event/process_memory_dump.cc
diff --git a/base/trace_event/process_memory_dump.cc b/base/trace_event/process_memory_dump.cc
index 0a3e0965f0bc0e24ec8934b4676608c2d8d20090..d3bb0a9d33d327c2f5fa2d84759962dd0b5d54c3 100644
--- a/base/trace_event/process_memory_dump.cc
+++ b/base/trace_event/process_memory_dump.cc
@@ -5,6 +5,7 @@
 #include "base/trace_event/process_memory_dump.h"
 
 #include "base/json/json_writer.h"
+#include "base/trace_event/process_memory_totals.h"
 #include "base/values.h"
 
 namespace base {
@@ -16,11 +17,18 @@ ProcessMemoryDump::ProcessMemoryDump() {
 ProcessMemoryDump::~ProcessMemoryDump() {
 }
 
+void ProcessMemoryDump::SetProcessTotals(scoped_ptr<ProcessMemoryTotals> pmt) {
+  process_totals_ = pmt.Pass();
+}
+
 void ProcessMemoryDump::AppendAsTraceFormat(std::string* out) const {
   // Build up the [dumper name] -> [serialized snapshot] JSON dictionary.
   DictionaryValue dict;
   std::string json_dict;
-  // TODO(primiano): this will append here the actual dumps from the dumpers.
+
+  if (process_totals_)
+    dict.Set("process_totals", process_totals_->AsValue());
+
   base::JSONWriter::Write(&dict, &json_dict);
   *out += json_dict;
 }